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Ratios: find the other quantity

Year 8 maths · Fieldbook Learning

Name ______________________ Date __________

Find what one part is worth, then multiply by the number of parts you need.

  1. The ratio of fiction books to non-fiction books is 9 : 5. There are 63 fiction books. How many non-fiction books are there?
  2. The ratio of apples to oranges is 6 : 3. There are 54 apples. How many oranges are there?
  3. The ratio of boys to girls is 1 : 2. There are 5 boys. How many girls are there?
  4. The ratio of boys to girls is 9 : 10. There are 27 boys. How many girls are there?
  5. The ratio of red marbles to blue marbles is 6 : 9. There are 24 red marbles. How many blue marbles are there?
  6. The ratio of fiction books to non-fiction books is 3 : 5. There are 12 fiction books. How many non-fiction books are there?
  7. The ratio of fiction books to non-fiction books is 2 : 12. There are 12 fiction books. How many non-fiction books are there?
  8. The ratio of red marbles to blue marbles is 2 : 4. There are 4 red marbles. How many blue marbles are there?
  9. The ratio of red marbles to blue marbles is 12 : 15. There are 48 red marbles. How many blue marbles are there?
  10. The ratio of fiction books to non-fiction books is 2 : 13. There are 6 fiction books. How many non-fiction books are there?
  11. The ratio of apples to oranges is 2 : 1. There are 28 apples. How many oranges are there?
  12. The ratio of cats to dogs is 6 : 2. There are 18 cats. How many dogs are there?
  13. The ratio of red marbles to blue marbles is 9 : 19. There are 99 red marbles. How many blue marbles are there?
  14. The ratio of boys to girls is 20 : 4. There are 320 boys. How many girls are there?
  15. The ratio of apples to oranges is 4 : 12. There are 36 apples. How many oranges are there?
  16. The ratio of red marbles to blue marbles is 10 : 3. There are 30 red marbles. How many blue marbles are there?
  17. The ratio of fiction books to non-fiction books is 30 : 22. There are 240 fiction books. How many non-fiction books are there?
  18. The ratio of fiction books to non-fiction books is 1 : 23. There are 16 fiction books. How many non-fiction books are there?
  19. The ratio of boys to girls is 7 : 5. There are 105 boys. How many girls are there?
  20. The ratio of apples to oranges is 2 : 29. There are 52 apples. How many oranges are there?
More free practice: fieldbooklearning.com/uk/practice/year-8/ratios-find-the-other-quantity/

Play it as a quiz game

14 of these questions as multiple choice, with near-miss wrong answers, ready for Kahoot or Blooket.

  1. Download the game's own question template: in Kahoot, Add question → Import spreadsheet; in Blooket, Create a set → Spreadsheet import.
  2. Click the matching button below, then click the first empty question row of the template and paste.
  3. Save the template (Kahoot needs .xlsx, Blooket .csv) and upload it.
Download CSV

Answer key: Ratios: find the other quantity

  1. 35
  2. 27
  3. 10
  4. 30
  5. 36
  6. 20
  7. 72
  8. 8
  9. 60
  10. 39
  11. 14
  12. 6
  13. 209
  14. 64
  15. 108
  16. 9
  17. 176
  18. 368
  19. 75
  20. 754